Preface

This special issue follows the associated Special Session SS34 with the same name from The 13th AIMS Conference on Dynamical Systems, Differential Equations and Applications in Wilmington, USA (May 31 -June 4, 2023).The focus of this session was the qualitative analysis of nonlinear differential problems.In particular, the main purpose was to give an update on recent developments concerning ordinary and partial differential equations, variational-hemivariational inequalities, difference, and algebraic systems obtained by exploiting different methods of the nonlinear analysis such as critical point theory, fixed point theorems, topological degree, Morse theory, set-valued analysis, and so on.We would like to thank all of the authors for their valuable scientific contributions and all of our colleagues for their support and cooperation, without which we could not have produced this volume.In addition, we would like to thank